Cutting allowance, also known as machining allowance, is defined as surplus dimensions provided in advance in a material to allow finishing to the prescribed dimensions in cutting (see, for example, “Dictionary of Mechanical Terms,” Nikkan Kogyo Shimbun, Ltd., Nov. 28, 1997, First Printing of First Edition).
It is also possible to provide cutting allowance for objects that are to be shaped by three-dimensional shaping methods.
With three-dimensional shaping methods, however, it is indispensable to carry out a cutting step for the cutting allowance, after having added a lamination step for the cutting allowance by repeating several times the process of formation of a powder layer, flattening of the powder layer with a squeegee and sintering by irradiation with a laser beam or electron beam.
Nevertheless, reasonable objective standards have not been determined for such three-dimensional shaping methods, in terms of setting the cutting allowance in the lamination step and setting the order for the subsequent cutting steps.
Patent Document 1, incidentally, describes reduction in the amount of cutting allowance in three-dimensional shaping, but does not describe in any way setting the cutting allowance for the lamination step or setting the order for the subsequent cutting steps.
Moreover, no published technical literature can be found discussing at what stages cutting should be carried out after lamination in which the cutting allowance is added, in order to accomplish efficient and accurate shaping.